From e89bbf1049aac3625fdafe3657ed8d7d5373d351 Mon Sep 17 00:00:00 2001 From: Michael Chan Date: Thu, 25 Aug 2005 15:36:58 -0700 Subject: [BNX2]: remove atomics in tx Remove atomic operations in the fast tx path. Expensive atomic operations were used to keep track of the number of available tx descriptors. The new code uses the difference between the consumer and producer index to determine the number of free tx descriptors. As suggested by Jeff Garzik, the name of the inline function is changed to all lower case. Signed-off-by: Michael Chan Signed-off-by: David S. Miller --- drivers/net/bnx2.c | 35 +++++++++++++++++------------------ 1 file changed, 17 insertions(+), 18 deletions(-) (limited to 'drivers/net/bnx2.c') diff --git a/drivers/net/bnx2.c b/drivers/net/bnx2.c index 015ff790660..da903b3ebfb 100644 --- a/drivers/net/bnx2.c +++ b/drivers/net/bnx2.c @@ -107,6 +107,15 @@ static struct flash_spec flash_table[] = MODULE_DEVICE_TABLE(pci, bnx2_pci_tbl); +static inline u32 bnx2_tx_avail(struct bnx2 *bp) +{ + u32 diff = TX_RING_IDX(bp->tx_prod) - TX_RING_IDX(bp->tx_cons); + + if (diff > MAX_TX_DESC_CNT) + diff = (diff & MAX_TX_DESC_CNT) - 1; + return (bp->tx_ring_size - diff); +} + static u32 bnx2_reg_rd_ind(struct bnx2 *bp, u32 offset) { @@ -1338,22 +1347,19 @@ bnx2_tx_int(struct bnx2 *bp) } } - atomic_add(tx_free_bd, &bp->tx_avail_bd); + bp->tx_cons = sw_cons; if (unlikely(netif_queue_stopped(bp->dev))) { unsigned long flags; spin_lock_irqsave(&bp->tx_lock, flags); if ((netif_queue_stopped(bp->dev)) && - (atomic_read(&bp->tx_avail_bd) > MAX_SKB_FRAGS)) { + (bnx2_tx_avail(bp) > MAX_SKB_FRAGS)) { netif_wake_queue(bp->dev); } spin_unlock_irqrestore(&bp->tx_lock, flags); } - - bp->tx_cons = sw_cons; - } static inline void @@ -2971,7 +2977,6 @@ bnx2_init_tx_ring(struct bnx2 *bp) bp->tx_prod = 0; bp->tx_cons = 0; bp->tx_prod_bseq = 0; - atomic_set(&bp->tx_avail_bd, bp->tx_ring_size); val = BNX2_L2CTX_TYPE_TYPE_L2; val |= BNX2_L2CTX_TYPE_SIZE_L2; @@ -4057,9 +4062,7 @@ bnx2_start_xmit(struct sk_buff *skb, struct net_device *dev) u16 prod, ring_prod; int i; - if (unlikely(atomic_read(&bp->tx_avail_bd) < - (skb_shinfo(skb)->nr_frags + 1))) { - + if (unlikely(bnx2_tx_avail(bp) < (skb_shinfo(skb)->nr_frags + 1))) { netif_stop_queue(dev); printk(KERN_ERR PFX "%s: BUG! Tx ring full when queue awake!\n", dev->name); @@ -4156,8 +4159,6 @@ bnx2_start_xmit(struct sk_buff *skb, struct net_device *dev) prod = NEXT_TX_BD(prod); bp->tx_prod_bseq += skb->len; - atomic_sub(last_frag + 1, &bp->tx_avail_bd); - REG_WR16(bp, MB_TX_CID_ADDR + BNX2_L2CTX_TX_HOST_BIDX, prod); REG_WR(bp, MB_TX_CID_ADDR + BNX2_L2CTX_TX_HOST_BSEQ, bp->tx_prod_bseq); @@ -4166,16 +4167,14 @@ bnx2_start_xmit(struct sk_buff *skb, struct net_device *dev) bp->tx_prod = prod; dev->trans_start = jiffies; - if (unlikely(atomic_read(&bp->tx_avail_bd) <= MAX_SKB_FRAGS)) { + if (unlikely(bnx2_tx_avail(bp) <= MAX_SKB_FRAGS)) { unsigned long flags; spin_lock_irqsave(&bp->tx_lock, flags); - if (atomic_read(&bp->tx_avail_bd) <= MAX_SKB_FRAGS) { - netif_stop_queue(dev); - - if (atomic_read(&bp->tx_avail_bd) > MAX_SKB_FRAGS) - netif_wake_queue(dev); - } + netif_stop_queue(dev); + + if (bnx2_tx_avail(bp) > MAX_SKB_FRAGS) + netif_wake_queue(dev); spin_unlock_irqrestore(&bp->tx_lock, flags); } -- cgit v1.2.3